The present invention relates to a steering control apparatus for motor vehicles, which changes the ratio of the steering angle of a steering handle or steering wheel to the turning angle of a steered wheel.
Various so-called steering control apparatus are proposed which comprise a variable gear-ratio mechanism on a steering-force transfer path between the steering handle and the steered wheel, wherein the gear ratio of the turning angle of the steered wheel, i.e. steering-angle ratio, is changed in accordance with the steering angle of the steering handle to achieve a larger control amount of the turning angle of the steered wheel at a smaller steering angle of the steering handle. One of the steering control apparatus is disclosed in JP-A 10-305779 wherein the variable gear-ratio mechanism comprises a friction-type continuously variable transmission.
With the above steering control apparatus, however, the control range and variation of the gear ratio cannot be set optionally freely using the vehicle speed as a control parameter, leading to difficulty of achieving optimum control in accordance with the vehicle speed and vehicle type.
It is, therefore, an object of the present invention to provide a steering control apparatus for motor vehicle, which allows optimum control in accordance with the vehicle speed and vehicle type.
The present invention provides generally a steering control apparatus for a motor vehicle which comprises an output shaft which steers a steered wheel; a slider arranged on an outer periphery of an end of the output shaft, the slider being slidable axially linearly; a converting mechanism arranged between the output shaft and the slider, wherein the converting mechanism converts linear motion of the slider into rotary motion which is transmitted to the output shaft; a drive mechanism which urges the slider to stroke axially; and an electronic control unit (ECU) which controls the drive mechanism.
A main feature of the present invention is to provide a steering control apparatus for a motor vehicle which comprises an input shaft rotated by a steering handle; an output shaft arranged substantially coaxial with the input shaft, the output shaft steering a steered wheel; a slider arranged on an outer periphery of an end of the output shaft on the side of the input shaft and at an end of the input shaft on the side of the output shaft, the slider being slidable axially linearly; a converting mechanism arranged between the output shaft and the slider, wherein the converting mechanism converts linear motion of the slider into rotary motion which is transmitted to the output shaft; a drive mechanism which urges the slider to stroke axially; and an electronic control unit (ECU) which controls the drive mechanism.